// Copyright (c) 2008, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//     * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// Author: Shinichiro Hamaji

#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include "base/googleinit.h"
#include "utilities.h"

#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#include <time.h>
#if defined(HAVE_SYSCALL_H)
#include <syscall.h> // for syscall()
#elif defined(HAVE_SYS_SYSCALL_H)
#include <sys/syscall.h> // for syscall()
#endif
#ifdef HAVE_SYSLOG_H
#include <syslog.h>
#endif

using std::string;

_START_GOOGLE_NAMESPACE_

static const char *g_program_invocation_short_name = NULL;
static pthread_t g_main_thread_id;

_END_GOOGLE_NAMESPACE_

// The following APIs are all internal.
#ifdef HAVE_STACKTRACE

#include "symbolize.h"
#include "base/stacktrace.h"
#include "base/commandlineflags.h"

GLOG_DEFINE_bool(symbolize_stacktrace, true,
                 "Symbolize the stack trace in the tombstone");

_START_GOOGLE_NAMESPACE_

typedef void DebugWriter(const char *, void *);

// The %p field width for printf() functions is two characters per byte.
// For some environments, add two extra bytes for the leading "0x".
static const int kPrintfPointerFieldWidth = 2 + 2 * sizeof(void *);

static void DebugWriteToStderr(const char *data, void *)
{
  // This one is signal-safe.
  if (write(STDERR_FILENO, data, strlen(data)) < 0)
  {
    // Ignore errors.
  }
}

void DebugWriteToString(const char *data, void *arg)
{
  reinterpret_cast<string *>(arg)->append(data);
}

#ifdef HAVE_SYMBOLIZE
// Print a program counter and its symbol name.
static void DumpPCAndSymbol(DebugWriter *writerfn, void *arg, void *pc,
                            const char *const prefix)
{
  char tmp[1024];
  const char *symbol = "(unknown)";
  // Symbolizes the previous address of pc because pc may be in the
  // next function.  The overrun happens when the function ends with
  // a call to a function annotated noreturn (e.g. CHECK).
  if (Symbolize(reinterpret_cast<char *>(pc) - 1, tmp, sizeof(tmp)))
  {
    symbol = tmp;
  }
  char buf[1024];
  snprintf(buf, sizeof(buf), "%s@ %*p  %s\n",
           prefix, kPrintfPointerFieldWidth, pc, symbol);
  writerfn(buf, arg);
}
#endif

static void DumpPC(DebugWriter *writerfn, void *arg, void *pc,
                   const char *const prefix)
{
  char buf[100];
  snprintf(buf, sizeof(buf), "%s@ %*p\n",
           prefix, kPrintfPointerFieldWidth, pc);
  writerfn(buf, arg);
}

// Dump current stack trace as directed by writerfn
static void DumpStackTrace(int skip_count, DebugWriter *writerfn, void *arg)
{
  // Print stack trace
  void *stack[32];
  int depth = GetStackTrace(stack, ARRAYSIZE(stack), skip_count + 1);
  for (int i = 0; i < depth; i++)
  {
#if defined(HAVE_SYMBOLIZE)
    if (FLAGS_symbolize_stacktrace)
    {
      DumpPCAndSymbol(writerfn, arg, stack[i], "    ");
    }
    else
    {
      DumpPC(writerfn, arg, stack[i], "    ");
    }
#else
    DumpPC(writerfn, arg, stack[i], "    ");
#endif
  }
}

static void DumpStackTraceAndExit()
{
  DumpStackTrace(1, DebugWriteToStderr, NULL);

  // TOOD(hamaji): Use signal instead of sigaction?
#ifdef HAVE_SIGACTION
  if (IsFailureSignalHandlerInstalled())
  {
    // Set the default signal handler for SIGABRT, to avoid invoking our
    // own signal handler installed by InstallFailureSignalHandler().
    struct sigaction sig_action;
    memset(&sig_action, 0, sizeof(sig_action));
    sigemptyset(&sig_action.sa_mask);
    sig_action.sa_handler = SIG_DFL;
    sigaction(SIGABRT, &sig_action, NULL);
  }
#endif // HAVE_SIGACTION

  abort();
}

_END_GOOGLE_NAMESPACE_

#endif // HAVE_STACKTRACE

_START_GOOGLE_NAMESPACE_

namespace glog_internal_namespace_
{

  const char *ProgramInvocationShortName()
  {
    if (g_program_invocation_short_name != NULL)
    {
      return g_program_invocation_short_name;
    }
    else
    {
      // TODO(hamaji): Use /proc/self/cmdline and so?
      return "UNKNOWN";
    }
  }

  bool IsGoogleLoggingInitialized()
  {
    return g_program_invocation_short_name != NULL;
  }

  bool is_default_thread()
  {
    if (g_program_invocation_short_name == NULL)
    {
      // InitGoogleLogging() not yet called, so unlikely to be in a different
      // thread
      return true;
    }
    else
    {
      return pthread_equal(pthread_self(), g_main_thread_id);
    }
  }

#ifdef OS_WINDOWS
  struct timeval
  {
    long tv_sec, tv_usec;
  };

  // Based on: http://www.google.com/codesearch/p?hl=en#dR3YEbitojA/os_win32.c&q=GetSystemTimeAsFileTime%20license:bsd
  // See COPYING for copyright information.
  static int gettimeofday(struct timeval *tv, void *tz)
  {
#define EPOCHFILETIME (116444736000000000ULL)
    FILETIME ft;
    LARGE_INTEGER li;
    uint64 tt;

    GetSystemTimeAsFileTime(&ft);
    li.LowPart = ft.dwLowDateTime;
    li.HighPart = ft.dwHighDateTime;
    tt = (li.QuadPart - EPOCHFILETIME) / 10;
    tv->tv_sec = tt / 1000000;
    tv->tv_usec = tt % 1000000;

    return 0;
  }
#endif

  int64 CycleClock_Now()
  {
    // TODO(hamaji): temporary impementation - it might be too slow.
    struct timeval tv;
    gettimeofday(&tv, NULL);
    return static_cast<int64>(tv.tv_sec) * 1000000 + tv.tv_usec;
  }

  int64 UsecToCycles(int64 usec)
  {
    return usec;
  }

  WallTime WallTime_Now()
  {
    // Now, cycle clock is retuning microseconds since the epoch.
    return CycleClock_Now() * 0.000001;
  }

  static int32 g_main_thread_pid = getpid();
  int32 GetMainThreadPid()
  {
    return g_main_thread_pid;
  }

  bool PidHasChanged()
  {
    int32 pid = getpid();
    if (g_main_thread_pid == pid)
    {
      return false;
    }
    g_main_thread_pid = pid;
    return true;
  }

  pid_t GetTID()
  {
    // On Linux and MacOSX, we try to use gettid().
#if defined OS_LINUX || defined OS_MACOSX
#ifndef __NR_gettid
#ifdef OS_MACOSX
#define __NR_gettid SYS_gettid
#elif !defined __i386__
#error "Must define __NR_gettid for non-x86 platforms"
#else
#define __NR_gettid 224
#endif
#endif
    static bool lacks_gettid = false;
    if (!lacks_gettid)
    {
      pid_t tid = syscall(__NR_gettid);
      if (tid != -1)
      {
        return tid;
      }
      // Technically, this variable has to be volatile, but there is a small
      // performance penalty in accessing volatile variables and there should
      // not be any serious adverse effect if a thread does not immediately see
      // the value change to "true".
      lacks_gettid = true;
    }
#endif // OS_LINUX || OS_MACOSX

    // If gettid() could not be used, we use one of the following.
#if defined OS_LINUX
    return getpid(); // Linux:  getpid returns thread ID when gettid is absent
#elif defined OS_WINDOWS || defined OS_CYGWIN
    return GetCurrentThreadId();
#else
    // If none of the techniques above worked, we use pthread_self().
    return (pid_t)(uintptr_t)pthread_self();
#endif
  }

  const char *const_basename(const char *filepath)
  {
    const char *base = strrchr(filepath, '/');
#ifdef OS_WINDOWS // Look for either path separator in Windows
    if (!base)
      base = strrchr(filepath, '\\');
#endif
    return base ? (base + 1) : filepath;
  }

  static string g_my_user_name;
  const string &MyUserName()
  {
    return g_my_user_name;
  }
  static void MyUserNameInitializer()
  {
    // TODO(hamaji): Probably this is not portable.
#if defined(OS_WINDOWS)
    const char *user = getenv("USERNAME");
#else
    const char *user = getenv("USER");
#endif
    if (user != NULL)
    {
      g_my_user_name = user;
    }
    else
    {
      g_my_user_name = "invalid-user";
    }
  }
  REGISTER_MODULE_INITIALIZER(utilities, MyUserNameInitializer());

#ifdef HAVE_STACKTRACE
  void DumpStackTraceToString(string *stacktrace)
  {
    DumpStackTrace(1, DebugWriteToString, stacktrace);
  }
#endif

  // We use an atomic operation to prevent problems with calling CrashReason
  // from inside the Mutex implementation (potentially through RAW_CHECK).
  static const CrashReason *g_reason = 0;

  void SetCrashReason(const CrashReason *r)
  {
    sync_val_compare_and_swap(&g_reason,
                              reinterpret_cast<const CrashReason *>(0),
                              r);
  }

  void InitGoogleLoggingUtilities(const char *argv0)
  {
    CHECK(!IsGoogleLoggingInitialized())
        << "You called InitGoogleLogging() twice!";
    const char *slash = strrchr(argv0, '/');
#ifdef OS_WINDOWS
    if (!slash)
      slash = strrchr(argv0, '\\');
#endif
    g_program_invocation_short_name = slash ? slash + 1 : argv0;
    g_main_thread_id = pthread_self();

#ifdef HAVE_STACKTRACE
    InstallFailureFunction(&DumpStackTraceAndExit);
#endif
  }

  void ShutdownGoogleLoggingUtilities()
  {
    CHECK(IsGoogleLoggingInitialized())
        << "You called ShutdownGoogleLogging() without calling InitGoogleLogging() first!";
    g_program_invocation_short_name = NULL;
#ifdef HAVE_SYSLOG_H
    closelog();
#endif
  }

} // namespace glog_internal_namespace_

_END_GOOGLE_NAMESPACE_

// Make an implementation of stacktrace compiled.
#ifdef STACKTRACE_H
#include STACKTRACE_H
#endif
